| 摘要 |
A method (Fig. 1) of recovering overerased bits in a memory cell. In the method, a pair of reference currents (I11H, I11L) are internally generated (301) to define a current window corresponding to the erased state ("11") of the memory cell. The first reference current defines the highest current of the current window (12) and the second reference current defines the lowest current of the current window. Then, it is determined (302) which of the memory cells in a memory array are in an overerased state (13) by having an amount of charge on its floating gate that corresponds to a conduction curre nt during a read operation that is greater than the first reference current. Then, the overerased cells are programmed (303; Fig. 8) until the cells are in the erased state.
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